Emmatine Haskell (Ernestine Barrier), an out-of-town buyer, reports that her purse, which contained $6000, is missing. Detectives Friday (Jack Webb) and Smith (Ben Alexander) based their investigation on Ms. Haskell's belief that she left her purse in a taxicab. A humble five-dollar bill proves to be the "clincher" in this particular mystery. "The Big Fin" is one of a handful of black and white Dragnet episodes not based on a previous radio version. ~ Hal Erickson, Rovi